The present invention is directed generally to fluorinated epoxy fluoropolymer compositions for use as protective surface coatings on various substrates such as metal, wood, plastic, paper and the like. This invention relates to novel 100 percent solids fluorinated epoxy fluoropolymer coating compositions. In another aspect, the invention relates to novel coating compositions and the process for producing the coating compositions which have excellent corrosion resistance and good adhesion as well as good release properties and hydrophobicity.
There is demand in the industry for protective coatings that will withstand the effects of a variety of severe environmental conditions. Many varieties of coating compositions are currently available that are based on various polymeric materials. Coating compositions containing highly fluorinated epoxy resin, generally can be made by dissolving the resins in suitable solvents and then adding to this solution suitable highly fluorinated fillers. Solvent based coatings are disadvantageous in that large amounts of volatile organic solvents are present. These solvents may be costly and hazardous. The solvents must be removed from the final coatings which requires considerable thermal energy. Further, if hazardous, the solvents must be recovered or incinerated as they may not be exhausted into the environment. Water based coatings are disadvantageous in that they are not continuous and have been found to contain more pinholes and voids than the solvent based coatings.
As a result, the search for an essentially solvent-free coating process has led to the use of solventless systems. The advantages of a solventless coating system includes the minimization of surface defects due to the absence of solvents and excellent heat and chemical resistance.
Hydrophobicity is a property needed in coatings so that they can withstand varied environmental conditions. Epoxy fluorocarbon coatings are limited in their hydrophobic properties by the level of fluorocarbon that can be dispersed in the coating composition. The fluorine content can be increased by employing fluorine in the epoxy matrix backbone of an epoxy fluorocarbon polymer of the instant invention thereby increasing the hydrophobicity of the coating composition.
It is an object of this invention to provide a fluorinated epoxy fluoropolymer coating composition in a 100 percent solids, solvent free system to avoid use of cyclable solvents. It is another object of this invention to employ fluorine in the epoxy matrix backbone of the epoxy fluorocarbon polymer resulting in an improved hydrophobic coating composition. It is another object of this invention to produce a coating composition that exhibits excellent adhesion and wetting to the substrate, good flexibility, hydrophobicity and excellent corrosion resistance.
These and other objects, together with the advantages over known methods shall become apparent from the specification which follows and are accomplished by the invention as hereinafter described and claimed.